Case 8-3-2010 - Turner's

Good Job Dr. Van Beek - The answer is Turner's

The key finding is a short 4th metacarpal. There is a differential for this finding. Idiopathic is the most common followed by trauma.

If unsure if metacarpal is shortened can use the metacarpal sign - draw a line that abuts the articular surface of the 4th and 5th digits - the continuation of the line should either abut the articular surface (or really small portion of the head) of the 3rd or not touch it at all. If it transects the 3rd - the 4th and/or 5th digit is short

Sicle Cell/Thalassemia - usually diffuse osseous abnormalities but is often asymmetric

Juvenile idiopathic arthritis - often asymmetric but extensive involvement is common; look for overgrown epiphyses.

Turner's (XO) syndrome has a high association with short 4th metacarpal. It can also be seen involving the 3rd and 5th metacarpals but 4th is most common. May see Madelung deformity of the carpus bones and may see metaphyseal excresences. Resnick describes findings of "drumstick" phalanges and thin bones.

Pseudohypoparathyroidism/Pseudo-Pseudohypoparathyroidism - 4th and 5th metacarpal shortening is most common and may see 1st as well; may see soft tissue and basal ganglia dystrophic calcification; End organ resistance to parathyroid hormone - therefore PTH is elevated and may see osteopenia with variable features of hyperparathyroidism

Hypoparathyroidism - 4th and 5th usually most involved but may have diffuse shortening.

VATER - radial sided shortening or absence

If all digits are involved the differential is different - hypothyroidism, mucopolysaccharidoses, achondroplasia, hypochondroplasia, Noonan syndrome, hypoparathryoidism, chondrodysplasia punctata.

As always - Please don't steal images without asking.

References - StatDx.com and http://chorus.rad.mcw.edu/doc/00368.html ; Bone and Joint Imaging by Resnick and Kransdorf

You Are Not Forgotten

Sorry, I am studying for Boards. By late May/early June - I will be back. Have fun and I promise the site will be even better.

Rob's radiology

NM Cases 1, 2 and 5

Case 1 - no activity on Pertechnetate scan - most likely subacute thyroiditis

Case 2 - Single nodule with intense uptake and suppression of the rest of thyroid - autonomous nodule

Case 5- Cold Nodule - concern for thyroid carcinoma which is what it turned out to be.

• I-123 and Technitium-99m pertechnetate are most commonly used imaging radionuclides
• I-131 can also be used for uptake
• I-131 - Beta emitter and has 1/2 life of 8 days. principal gamma emission is 364 emitter. I-131 advantage - low price and ready availability. Disadvantage - long 1/2 life and high-beta emission (esp. to thyroid - about 1 rad/microCi); good for tumor follow up due to long half life
• I-123 - same behavior as iodine. Nuclide of choice for thyroid imaging. Decays by electron capture - 159 KeV and 1/2 of 13 hours. Low background activity. Disadvantages - high cost (produced by cyclotron), availability and delivery.
• Tech 99m - trapped by thyroid but not organified; 6 hour 1/2 life; 140 KeV - ideal for gamma camera; can give higher doses and acquire quickly w/ less risk of motion; higher background than iodine (only 1-5% trapped); Salivary glands - well seen; preferred nuclide when patient has been on thyroid blocking agents or unable to take medication orally or study must be completed in less than 2 hours.
• Both Tech and iodine - cross placenta and secreted in breast milk
• NRC recommends stopping breast feeding if I-131 exceeds 1 microCi
• I-131 - not recommended for children.
• Radioiodine Uptake test - Useful for clinical index of thyroid function.
• Often for determining how much uptake will be present for therapy.
• Useful for differentiating Grave's from subacute thyroiditis or factitious hyperthyroidism
• Basic idea - the more active the gland the more iodine will be taken up. Measurements obtained at 4-6 hours and 24 hours post administration.
• 4-6 - normal is 6-18%; 24 - 10-30%
• Patient should be NPO after midnight
• I-123 10-20 microCi; I-131 5 microCi
• Neck compared with neck phantom. Probe - 25-30 cm from anterior neck
• Equation - (neck counts-thigh counts)/counts in standard1
• 4-6 hour uptake recommended - esp for the possibility of a rapid turnover Grave's
• Factors affecting uptake - Too much iodine in diet (low uptake); too little (high uptake)
• Increased uptake factors - hyperthyroidism, early hashimoto's, recovery from subacute thyroiditis, Rebound after antithyroid meds; Enzyme defects; Iodine deficiency; Hypoalbuminemia; TSH; tumor secreted stimulators; Pregnancy
• Decreased uptake factors - hypothyroidism; iodine overload (contrast); meds; subacute or autoimmune thyroiditis; thyroid hormone tx; ectopic secretion from tumors (struma-ovarii etc); renal failure
• Compounds that decrease uptake - adrenocorticosteroids, amiodarone, bromides, butazolidine, Mercurials, methimazole, Propylthiouracil; nitrates; Perchlorate; salicylates; kelp, Cytomel, synthroid, contrast
• Renal failure - iodides are retained leading to larger pool of iodine which will compete with I-123 or I-1316.
• B-blockers - do not affect function of thyroid and does not affect uptake.
• Chronic Thyroiditis - Hashimoto's - most common form of inflammatory disease of thyroid
• Likely Autoimmune; usually female
• Thyromegaly - presenting w/ possibly mild hyperthyroidism or hypothyroidism
• Early - scan shows diffusely uniform like Grave's
• Later - coarse patchy activity - similar to multinodular goiter
• Acute (bacterial), subacute (viral or autoimmune) - usually diagnosed on clinical or physical grounds - scanning little role
• Subacute - painful swollen gland w/ elevated thyroid hormone levels but depressed uptake - little or no localization
• Cold Nodule - Most common - colloid cyst (70-75%)
• Carcinoma - 15-25% - this is why every cold nodule should get US and possible biopsy.
• Miscellaneous - <15%>
• Factors increasing risk of malignancy - younger patients, male, hx of rads to head and neck, hard lesion, other masses in neck, no shrinkage on thyroid hormone, family hx.
• Factors decreasing risk - older, female, sudden onset, tender or soft lesion, multiple nodules, shrinkage on thyroid hormone.
• US - useful for showing solid versus cystic (not benign vs malignant).
• Hot nodules almost always represent hyperfunctioning adenomas of which 1/2 are autonomous
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• Often not suppressible by thyroid hormone and independent of pituitary axis.
• Can suppress surrounding thyroid
• Warm - may represent a cold nodule that has overlying normal thyroid tissue - so have to get multiple views.

July 14 Cases 1-3 answers

Case 1 - 2 different examples of Meningioma.

Case 2 - BB to the eye.

Case 3 - Epidural hematoma.

Sorry my family got back from long trip so not a lot of time for detailed descriptions. Will do more later promise.

As far as Case 2 - the movie was -

Case 1 Answer 7-6-2009 Thyroid (Grave's) Ophthalmopathy

What we see is enlargement of the extraocular muscles that "spares" the myotendinous junction.

This is Thyroid Ophthalmopathy

• Usually occurs in patients with Grave's disease - but can be seen in any thyroid state


• Resolves in >90% of patients


• Most common cause of proptosis in adults


• Histology - inflammatory leukocytic infiltration with edema and deposition of mucopolysaccharides - leading to fibrosis, lipomatosis, fatty degeneration.


• Can compress optic nerve leading to optic neuropathy


• Can cause diplopia due to muscle entrapment


• Proptosis - can lead to corneal ulcers and conjunctival congestion


• Most frequently involves medial and inferior recti - IMSLow - Inferior, medial, superior, lateral; muscles >4 mm


• More frequent in women but more severe in men


• Expansion of orbital fat


• Upper and lower eyelid retraction


• Often bilateral and symmetric


• Painless


• TX - prednisone, radiotherapy, surgical decompression, thyroid surgery, I-131


• DDX - pseudotumor (painful, unilateral, involves tendons, inflammed fat, good response to steroids) [can be idiopathic, sarcoid, endocrine, focal infections, foreign bodies], cavernous hemangioma of the orbit, Histiocytosis X, cavernous sinus thrombosis, intraconal varices, lacrimal gland tumor and don't forget mets (usually osseous)


• Imaging - Ultrasound, CT (good bone imaging and shows all the features but has radiation), MRI

References: http://emedicine.medscape.com/article/383412-overview ; Neuroradiology Companion by Mauricio Castillo and Primer of Diagnostic Imaging by Weissleder et al.

Case 2 Answer 7-6-2009 - Perineural spread.

The imaging demonstrates a lesion in Meckel's cave that is low on T1, dark on T2 and enhances. There is denervation atrophy of the pterygoid muscles on the right and opacification of the right mastoid air cells.

With imaging like this, you need to think of peritumoral spread along the cranial nerves. This is an odd example in that biopsy revealed Lymphoma.

• Perineural spread - tumor or other pathology spreads along tissues of neural sheath
• Common in head and neck cancer
• In head and neck cancer - major negative prognostic indicator
• Most common malignancies - salivary, mucosal and cutaneous
• Adenoid cystic frequently spreads by perineural tumor spread
• SCC of mucosal and cutaneous can
• Desmoplastic melanoma is common
• Often present at time of diagnosis; rarely present prior to detection
• Can present as recurrence or occur at the same time as recurrence
• Common hx - new cranial neuropathy
• Any tumor that are adjacent the skull base foramina are at risk of Perineural tumor spread; esp - masticator space, Meckel's cave, cavernous sinus and Pterygopalatine fossa
• Perineural spread - can be retrograde (toward CNS) or antegrade (away from CNS)
• Benign - some benign disorders spread along cranial nerves (essentially like PNS or similar to it by imaging) - schwannoma/neurofibroma, meningioma, rhinocerebral mucormycosis, sarcoidosis etc.
• Signs and Symptoms - pain and paresthesias
• V3 - weakness and denervation of muscles of mastication
• Facial - variable weakness or paralysis
• Most commonly affected - trigeminal and facial
• V2 (maxillary) and V3 (mandibular) - most common branches of CN V involved
• V1 - sensory to eye, lacrimal gland, conjunctiva, some nasal mucosa and upper face
• V1 - often from cutaneous lesion in supraorbital region; rare for intraorbital process to spread to V1
• V2 - sensory to mid and upper lateral face, mucosa of palate, sinonasal region, maxillary gingiva and maxillary teeth
• V2 - to spread along V2 from nasopharynx - must access pterygopalatine fossa (PPF) - often by nasal cavity then sphenopalatine foramen
• V2 - from skin along maxillary distribution - infraorbital nerve or zygomatic nerve
• Pterygopalatine fossa - Pterygopalatine ganglion, internal maxillary artery; bounded posteriorly by pterygoid plates, medially by palatine bone, anteriorly by maxillary sinus
• PPF - communicates laterally with infratemporal fossa with pterygomaxillary fissure
• PPF - communicates w/ intracranial space by foramen rotundum
• PPF - communicates with nasal cavity (medially) via sphenopalatine foramen
• PPF - Vidian nerve provides preganglinonic parasympathetic component of pterygopalatine ganglion
• PPF - communicates with greater and lesser palatine foramina inferiorly through the palate
• V3 - sensory innervation to skin of lower face and pre-auricular/temporal region, mandibular teeth, mucosa of mandibular gingiva, floor of mouth, ant 2/3 of tongue, buccal mucosa
• V3 - motor to musscles of mastication, mylohyoid and anterior digastric
• V3 - PNS - travel through foramen Ovale to Meckel's cave
• Facial Nerve (CN VII) - typically only 2 branches are affected - descending facial nerve (from parotid malignancies or lesions that involve the parotid) and the GSPN (greater superficial petrosal nerve)
• Descending facial nerve - can travel to geniculate ganglionand even through labyrinthine segment to involve internal auditory canal
• GSPN - small branch that leaves geniculate ganglion and exits superior surface of temporal bonte through facial hiatus to become intracranial; courses anteromedially beneath Meckel's cave to foramen Lacerum to join deep petrosal nerve (carotid sympathetic plexus) and become the Vidian nerve through Vidian canal
• Imaging - minimum need axial T1, axial T2, and 3 plane postcon T1 (with at least one in fat-suppressed form)
• T1 - look for loss of normal fat
• Look for widening of foramina - foramen ovale, mandibular foramen, foramen rotundum, PPF, foramen and canal for infraorbital nerve, vidian canal, palatine foramen, stylomastoid foramen, descending facial canal
• Look for enhancement
• Look for involvement of Meckel's cave
• Indirect findings - denervation of masticator muscles, anterior digastric, mylohyoid
• Early denervation - T2 bright and enhancement with post con
• Late - atrophy and fatty infiltration

Reference - MR Imaging of Perineural Tumor Spread by Lawrence E. Ginsberg; Neuroimaging Clinics of North America 14 (2004) 663-667

6-27-2009 Case 2 answer - Capillary Telangiectasia

Lesion that is not seen on T1 precon but demonstrates "stipple" enhancement on postcontrast images in the pons - this is consistent with capillary telangiectasia.

• Most are in pons - but can be seen in cerebral, cerebellar and spinal cord tissue
• Nearly always asymptomatic and no further intervention necessary
• 16-20% of intracerebral vascular malformations at autopsy
• CT - almost always normal
• T1 - hypo to iso to brain
• T2 - normal (often) or slightly hyperintense
• T2* - can be normal or low in signal - but not due to hemorrhage or calcification - and likely represents deoxyhemoglobin in slow flowing blood
• T1 postcon - brush like or stippled pattern
• No mass effect
• 2/3 have enlarged vessel that may represent a draining vein.
• Often considered an acquired lesion and may represent obstructed venous drainage
• Can be seen in association with cavernomas and AVMs
• Does not show up on angiography

Reference - http://www.ajnr.org/cgi/content/full/22/8/1553 and http://emedicine.medscape.com/article/337451-overview